from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.graphics import Rectangle, Color

class mainCanvas(BoxLayout):
    def __init__(self, **kwargs):
        super(mainCanvas, self).__init__(**kwargs)
        with self.canvas:
            Color(0.2, 0.2, 0.2, 1)
            Rectangle(pos_hint={"x":0,"top":0}, size=(self.size[0],32))

class mainApp(App):
    def build(self):
        return mainCanvas(size_hint=(1,1))
            
mainApp().run()
